Viscosity-Reducing Excipient Compounds for Protein Formulations

ABSTRACT

The invention encompasses formulations and methods for the production thereof that permit the delivery of concentrated protein solutions. The inventive methods can yield a lower viscosity liquid formulation or a higher concentration of therapeutic or nontherapeutic proteins in the liquid formulation, as compared to traditional protein solutions.

RELATED APPLICATIONS

This application is a Continuation of U.S. application Ser. No. 14/966,549 filed Dec. 11, 2015, which claims the benefit of U.S. Provisional Application Ser. No. 62/014,784 filed Jun. 20, 2014, U.S. Provisional Application No. 62/083,623, filed Nov. 24, 2014, and U.S. Provisional Application Ser. No. 62/136,763 filed Mar. 23, 2015. The entire contents of the each of the above applications are incorporated by reference herein.

FIELD OF APPLICATION

This application relates generally to formulations for delivering biopolymers.

BACKGROUND

Biopolymers may be used for therapeutic or non-therapeutic purposes. Biopolymer-based therapeutics, such as antibody or enzyme formulations, are widely used in treating disease. Non-therapeutic biopolymers, such as enzymes, peptides, and structural proteins, have utility in non-therapeutic applications such as household, nutrition, commercial, and industrial uses.

Biopolymers used in therapeutic applications must be formulated to permit their introduction into the body for treatment of disease. For example, it is advantageous to deliver antibody and protein/peptide biopolymer formulations by subcutaneous (SC) or intramuscular (IM) routes under certain circumstances, instead of administering these formulations by intravenous (IV) injections. In order to achieve better patient compliance and comfort with SC or IM injection though, the liquid volume in the syringe is typically limited to 2 to 3 ccs and the viscosity of the formulation is typically lower than about 20 centipoise (cP) so that the formulation can be delivered using conventional medical devices and small-bore needles. These delivery parameters do not always fit well with the dosage requirements for the formulations being delivered.

Antibodies, for example, may need to be delivered at high dose levels to exert their intended therapeutic effect. Using a restricted liquid volume to deliver a high dose level of an antibody formulation can require a high concentration of the antibody in the delivery vehicle, sometimes exceeding a level of 150 mg/mL. At this dosage level, the viscosity-versus-concentration plots of protein solutions lie beyond their linear-nonlinear transition, such that the viscosity of the formulation rises dramatically with increasing concentration. Increased viscosity, however, is not compatible with standard SC or IM delivery systems. The solutions of biopolymer-based therapeutics are also prone to stability problems, such as precipitation, hazing, opalescence, denaturing, and gel formation, reversible or irreversible aggregation. The stability problems limit the shelf life of the solutions or require special handling.

One approach to producing protein formulations for injection is to transform the therapeutic protein solution into a powder that can be reconstituted to form a suspension suitable for SC or IM delivery. Lyophilization is a standard technique to produce protein powders. Freeze-drying, spray drying and even precipitation followed by super-critical-fluid extraction have been used to generate protein powders for subsequent reconstitution. Powdered suspensions are low in viscosity before re-dissolution (compared to solutions at the same overall dose) and thus may be suitable for SC or IM injection, provided the particles are sufficiently small to fit through the needle. However, protein crystals that are present in the powder have the inherent risk of triggering immune response. The uncertain protein stability/activity following re-dissolution poses further concerns. There remains a need in the art for techniques to produce low viscosity protein formulations for therapeutic purposes while avoiding the limitations introduced by protein powder suspensions.

In addition to the therapeutic applications of proteins described above, biopolymers such as enzymes, peptides, and structural proteins can be used in non-therapeutic applications. These non-therapeutic biopolymers can be produced from a number of different pathways, for example, derived from plant sources, animal sources, or produced from cell cultures.

The non-therapeutic proteins can be produced, transported, stored, and handled as a granular or powdered material or as a solution or dispersion, usually in water. The biopolymers for non-therapeutic applications can be globular or fibrous proteins, and certain forms of these materials can have limited solubility in water or exhibit high viscosity upon dissolution. These solution properties can present challenges to the formulation, handling, storage, pumping, and performance of the non-therapeutic materials, so there is a need for methods to reduce viscosity and improve solubility and stability of non-therapeutic protein solutions.

Proteins are complex biopolymers, each with a uniquely folded 3-D structure and surface energy map (hydrophobic/hydrophilic regions and charges). In concentrated protein solutions, these macromolecules may strongly interact and even inter-lock in complicated ways, depending on their exact shape and surface energy distribution. “Hot-spots” for strong specific interactions lead to protein clustering, increasing solution viscosity. To address these concerns, a number of excipient compounds are used in biotherapeutic formulations, aiming to reduce solution viscosity by impeding localized interactions and clustering. These efforts are individually tailored, often empirically, sometimes guided by in silico simulations. Combinations of excipient compounds may be provided, but optimizing such combinations again must progress empirically and on a case-by case basis.

There remains a need in the art for a truly universal approach to reducing viscosity in protein formulations at a given concentration under nonlinear conditions. There is an additional need in the art to achieve this viscosity reduction while preserving the activity of the protein. It would be further desirable to adapt the viscosity-reduction system to use with formulations having tunable and sustained release profiles, and to use with formulations adapted for depot injection.

SUMMARY OF THE INVENTION

Disclosed herein, in embodiments, are liquid formulations comprising a protein and an excipient compound selected from the group consisting of hindered amines, anionic aromatics, functionalized amino acids, oligopeptides, short-chain organic acids, and low molecular weight aliphatic polyacids, wherein the excipient compound is added in a viscosity-reducing amount. In embodiments, the protein is a PEGylated protein and the excipient is a low molecular weight aliphatic polyacid. In embodiments, the formulation is a pharmaceutical composition, and the therapeutic formulation comprises a therapeutic protein, wherein the excipient compound is a pharmaceutically acceptable excipient compound. In embodiments, the formulation is a non-therapeutic formulation, and the non-therapeutic formulation comprises a non-therapeutic protein. In embodiments, the viscosity-reducing amount reduces viscosity of the formulation to a viscosity less than the viscosity of a control formulation. In embodiments, the viscosity of the formulation is at least about 10% less than the viscosity of the control formulation, or is at least about 30% less than the viscosity of the control formulation, or is at least about 50% less than the viscosity of the control formulation, or is at least about 70% less than the viscosity of the control formulation, or is at least about 90% less than the viscosity of the control formulation. In embodiments, the viscosity is less than about 100 cP, or is less than about 50 cP, or is less than about 20 cP, or is less than about 10 cP. In embodiments, the excipient compound has a molecular weight of <5000 Da, or <1500 Da, or <500 Da. In embodiments, the formulation contains at least about 25 mg/mL of the protein, or at least about 100 mg/mL of the protein, or at least about 200 mg/mL of the protein, or at least about 300 mg/mL of the protein. In embodiments, the formulation comprises between about 5 mg/mL to about 300 mg/mL of the excipient compound, or comprises between about 10 mg/mL to about 200 mg/mL of the excipient compound, or comprises between about 20 mg/mL to about 100 mg/mL, or comprises between about 25 mg/mL to about 75 mg/mL of the excipient compound. In embodiments, the formulation has an improved stability when compared to the control formulation. In embodiments, the excipient compound is a hindered amine. In embodiments, the hindered amine is selected from the group consisting of caffeine, theophylline, tyramine, procaine, lidocaine, imidazole, aspartame, saccharin, and acesulfame potassium. In embodiments, the hindered amine is caffeine. In embodiments, the hindered amine is a local injectable anesthetic compound. The hindered amine can possess an independent pharmacological property, and the hindered amine can be present in the formulation in an amount that has an independent pharmacological effect. In embodiments the hindered amine can be present in the formulation in an amount that is less than a therapeutically effective amount. The independent pharmacological activity can be a local anesthetic activity. In embodiments, the hindered amine possessing possessing the independent pharmacological activity is combined with a second excipient compound that further decreases the viscosity of the formulation. The second excipient compound can be selected from the group consisting of caffeine, theophylline, tyramine, procaine, lidocaine, imidazole, aspartame, saccharin, and acesulfame potassium. In embodiments, the formulation can comprise an additional agent selected from the group consisting of preservatives, surfactants, sugars, polysaccharides, arginine, proline, hyaluronidase, stabilizers, and buffers.

Further disclosed herein are methods of treating a disease or disorder in a mammal, comprising administering to said mammal a liquid therapeutic formulation, wherein the therapeutic formulation comprises a therapeutically effective amount of a therapeutic protein, and wherein the formulation further comprises an pharmaceutically acceptable excipient compound selected from the group consisting of hindered amines, anionic aromatics, functionalized amino acids, oligopeptides, short-chain organic acids, and low molecular weight aliphatic polyacids; and wherein the therapeutic formulation is effective for the treatment of the disease or disorder. In embodiments, the therapeutic protein is a PEGylated protein, and the excipient compound is a low molecular weight aliphatic polyacid. In embodiments, the excipient is a hindered amine. In embodiments, the hindered amine is a local anesthetic compound. In embodiments, the formulation is administered by subcutaneous injection, or an intramuscular injection, or an intravenous injection. In embodiments, the excipient compound is present in the therapeutic formulation in a viscosity-reducing amount, and the viscosity-reducing amount reduces viscosity of the therapeutic formulation to a viscosity less than the viscosity of a control formulation. In embodiments, the therapeutic formulation has an improved stability when compared to the control formulation. In embodiments, the excipient compound is essentially pure.

Further disclosed herein are methods of reducing pain at an injection site of a therapeutic protein in a mammal in need thereof, comprising: administering a liquid therapeutic formulation by injection, wherein the therapeutic formulation comprises a therapeutically effective amount of the therapeutic protein, wherein the formulation further comprises an pharmaceutically acceptable excipient compound selected from the group consisting of local injectable anesthetic compounds, wherein the pharmaceutically acceptable excipient compound is added to the formulation in a viscosity-reducing amount; and wherein the mammal experiences less pain with administration of the therapeutic formulation comprising the excipient compound than that with administration of a control therapeutic formulation, wherein the control therapeutic formulation does not contain the excipient compound and is otherwise identical to the therapeutic formulation.

Disclosed herein, in embodiments, are methods of improving stability of a liquid protein formulation, comprising: preparing a liquid protein formulation comprising a therapeutic protein and an excipient compound selected from the group selected from the group consisting of hindered amines, anionic aromatics, functionalized amino acids, oligopeptides, and short-chain organic acids, and low molecular weight aliphatic polyacids, wherein the liquid protein formulation demonstrates improved stability compared to a control liquid protein formulation, wherein the control liquid protein formulation does not contain the excipient compound and is otherwise identical to the liquid protein formulation. The stability of the liquid formulation can be a cold storage conditions stability, a room temperature stability or an elevated temperature stability.

Also disclosed herein, in embodiments, are liquid formulations comprising a protein and an excipient compound selected from the group consisting of hindered amines, anionic aromatics, functionalized amino acids, oligopeptides, short-chain organic acids, and low molecular weight aliphatic polyacids, wherein the presence of the excipient compound in the formulation results in improved protein-protein interaction characteristics as measured by the protein diffusion interaction parameter kD, or the second virial coefficient B22. In embodiments, the formulation is a therapeutic formulation, and comprises a therapeutic protein. In embodiments, the formulation is a non-therapeutic formulation, and comprises a non-therapeutic protein.

Further disclosed herein, in embodiments, are methods of improving a protein-related process comprising providing the liquid formulation described above, and employing it in a processing method. In embodiments, the processing method includes filtration, pumping, mixing, centrifugation, membrane separation, lyophilization, or chromatography.

DETAILED DESCRIPTION

Disclosed herein are formulations and methods for their production that permit the delivery of concentrated protein solutions. In embodiments, the approaches disclosed herein can yield a lower viscosity liquid formulation or a higher concentration of therapeutic or nontherapeutic proteins in the liquid formulation, as compared to traditional protein solutions. In embodiments, the approaches disclosed herein can yield a liquid formulation having improved stability when compared to a traditional protein solution. A stable formulation is one in which the protein contained therein substantially retains its physical and chemical stability and its therapeutic or nontherapeutic efficacy upon storage under storage conditions, whether cold storage conditions, room temperature conditions, or elevated temperature storage conditions. Advantageously, a stable formulation can also offer protection against aggregation or precipitation of the proteins dissolved therein. For example, the cold storage conditions can entail storage in a refrigerator or freezer. In some examples, cold storage conditions can entail conventional refrigerator or freezer storage at a temperature of 10° C. or less. In additional examples, the cold storage conditions entail storage at a temperature from about 2° to about 10° C. In other examples, the cold storage conditions entail storage at a temperature of about 4° C. In additional examples, the cold storage conditions entail storage at freezing temperature such as about 0° C. or lower. In another example, cold storage conditions entail storage at a temperature of about −30° C. to about 0° C. The room temperature storage conditions can entail storage at ambient temperatures, for example, from about 10° C. to about 30° C. Elevated temperature stability, for example, at temperatures from about 30° C. to about 50° C., can be used as part of an accelerated aging study to predict the long term storage at typical ambient (10-30° C.) conditions.

It is well known to those skilled in the art of polymer science and engineering that proteins in solution tend to form entanglements, which can limit the translational mobility of the entangled chains and interfere with the protein's therapeutic or nontherapeutic efficacy. In embodiments, excipient compounds as disclosed herein can suppress protein clustering due to specific interactions between the excipient compound and the target protein in solution. Excipient compounds as disclosed herein can be natural or synthetic, and desirably are substances that the FDA generally recognizes as safe (“GRAS”).

1. Definitions

For the purpose of this disclosure, the term “protein” refers to a sequence of amino acids having a chain length long enough to produce a discrete tertiary structure, typically having a molecular weight between 1-3000 kD. In some embodiments, the molecular weight of the protein is between about 50-200 kD; in other embodiments, the molecular weight of the protein is between about 20-1000 kD or between about 20-2000 kD. In contrast to the term “protein,” the term “peptide” refers to a sequence of amino acids that does not have a discrete tertiary structure. A wide variety of biopolymers are included within the scope of the term “protein.” For example, the term “protein” can refer to therapeutic or non-therapeutic proteins, including antibodies, aptamers, fusion proteins, PEGylated proteins, synthetic polypeptides, protein fragments, lipoproteins, enzymes, structural peptides, and the like.

As non-limiting examples, therapeutic proteins can include mammalian proteins such as hormones and prohormones (e.g., insulin and proinsulin, glucagon, calcitonin, thyroid hormones (T3 or T4 or thyroid-stimulating hormone), parathyroid hormone, follicle-stimulating hormone, luteinizing hormone, growth hormone, growth hormone releasing factor, and the like); clotting and anti-clotting factors (e.g., tissue factor, von Willebrand's factor, Factor VIIIC, Factor IX, protein C, plasminogen activators (urokinase, tissue-type plasminogen activators), thrombin); cytokines, chemokines, and inflammatory mediators; interferons; colony-stimulating factors; interleukins (e.g., IL-1 through IL-10); growth factors (e.g., vascular endothelial growth factors, fibroblast growth factor, platelet-derived growth factor, transforming growth factor, neurotrophic growth factors, insulin-like growth factor, and the like); albumins; collagens and elastins; hematopoietic factors (e.g., erythropoietin, thrombopoietin, and the like); osteoinductive factors (e.g., bone morphogenetic protein); receptors (e.g., integrins, cadherins, and the like); surface membrane proteins; transport proteins; regulatory proteins; antigenic proteins (e.g., a viral component that acts as an antigen); and antibodies. The term “antibody” is used herein in its broadest sense, to include as non-limiting examples monoclonal antibodies (including, for example, full-length antibodies with an immunoglobulin Fc region), single-chain molecules, bi-specific and multi-specific antibodies, diabodies, antibody compositions having polyepitopic specificity, and fragments of antibodies (including, for example, Fab, Fv, and F(ab′)2). Antibodies can also be termed “immunoglobulins.” An antibody is understood to be directed against a specific protein or non-protein “antigen,” which is a biologically important material; the administration of a therapeutically effective amount of an antibody to a patient can complex with the antigen, thereby altering its biological properties so that the patient experiences a therapeutic effect.

In embodiments, the proteins are PEGylated, meaning that they comprise poly(ethylene glycol) (“PEG”) and/or poly(propylene glycol) (“PPG”) units. PEGylated proteins, or PEG-protein conjugates, have found utility in therapeutic applications due to their beneficial properties such as solubility, pharmacokinetics, pharmacodynamics, immunogenicity, renal clearance, and stability. Non-limiting examples of PEGylated proteins are PEGylated interferons (PEG-IFN), PEGylated anti-VEGF, PEG protein conjugate drugs, Adagen, Pegaspargase, Pegfilgrastim, Pegloticase, Pegvisomant, PEGylated epoetin-β, and Certolizumab pegol.

PEGylated proteins can be synthesized by a variety of methods such as a reaction of protein with a PEG reagent having one or more reactive functional groups. The reactive functional groups on the PEG reagent can form a linkage with the protein at targeted protein sites such as lysine, histidine, cysteine, and the N-terminus. Typical PEGylation reagents have reactive functional groups such as aldehyde, maleimide, or succinimide groups that have specific reactivity with targeted amino acid residues on proteins. The PEGylation reagents can have a PEG chain length from about 1 to about 1000 PEG and/or PPG repeating units. Other methods of PEGylation include glyco-PEGylation, where the protein is first glycosylated and then the glycosylated residues are PEGylated in a second step. Certain PEGylation processes are assisted by enzymes like sialyltransferase and transglutaminase.

While the PEGylated proteins can offer therapeutic advantages over native, non-PEGylated proteins, these materials can have physical or chemical properties that make them difficult to purify, dissolve, filter, concentrate, and administer. The PEGylation of a protein can lead to a higher solution viscosity compared to the native protein, and this generally requires the formulation of PEGylated protein solutions at lower concentrations.

It is desirable to formulate protein therapeutics in stable, low viscosity solutions so they can be administered to patients in a minimal injection volume. For example, the subcutaneous (SC) or intramuscular (IM) injection of drugs generally requires a small injection volume, preferably less than 2 mL. The SC and IM injection routes are well suited to self-administered care, and this is a less costly and more accessible form of treatment compared with intravenous (IV) injection which is only conducted under direct medical supervision. Formulations for SC or IM injection require a low solution viscosity, generally below 30 cP, and preferably below 20 cP, to allow easy flow of the therapeutic solution through a narrow gauge needle. This combination of small injection volume and low viscosity requirements present a challenge to the use of PEGylated protein therapeutics in SC or IM injection routes.

Those proteins having therapeutic effects may be termed “therapeutic proteins”; formulations containing therapeutic proteins in therapeutically effective amounts may be termed “therapeutic formulations.” The therapeutic protein contained in a therapeutic formulation may also be termed its “protein active ingredient.” Typically, a therapeutic formulation comprises a therapeutically effective amount of a protein active ingredient and an excipient, with or without other optional components. As used herein, the term “therapeutic” includes both treatments of existing disorders and preventions of disorders.

A “treatment” includes any measure intended to cure, heal, alleviate, improve, remedy, or otherwise beneficially affect the disorder, including preventing or delaying the onset of symptoms and/or alleviating or ameliorating symptoms of the disorder. Those patients in need of a treatment include both those who already have a specific disorder, and those for whom the prevention of a disorder is desirable. A disorder is any condition that alters the homeostatic wellbeing of a mammal, including acute or chronic diseases, or pathological conditions that predispose the mammal to an acute or chronic disease. Non-limiting examples of disorders include cancers, metabolic disorders (e.g., diabetes), allergic disorders (e.g., asthma), dermatological disorders, cardiovascular disorders, respiratory disorders, hematological disorders, musculoskeletal disorders, inflammatory or rheumatological disorders, autoimmune disorders, gastrointestinal disorders, urological disorders, sexual and reproductive disorders, neurological disorders, and the like. The term “mammal” for the purposes of treatment can refer to any animal classified as a mammal, including humans, domestic animals, pet animals, farm animals, sporting animals, working animals, and the like. A “treatment” can therefore include both veterinary and human treatments. For convenience, the mammal undergoing such “treatment” can be referred to as a “patient.” In certain embodiments, the patient can be of any age, including fetal animals in utero.

In embodiments, a treatment involves providing a therapeutically effective amount of a therapeutic formulation to a mammal in need thereof. A “therapeutically effective amount” is at least the minimum concentration of the therapeutic protein administered to the mammal in need thereof, to effect a treatment of an existing disorder or a prevention of an anticipated disorder (either such treatment or such prevention being a “therapeutic intervention”). Therapeutically effective amounts of various therapeutic proteins that may be included as active ingredients in the therapeutic formulation may be familiar in the art; or, for therapeutic proteins discovered or applied to therapeutic interventions hereinafter, the therapeutically effective amount can be determined by standard techniques carried out by those having ordinary skill in the art, using no more than routine experimentation.

Those proteins used for non-therapeutic purposes (i.e., purposes not involving treatments), such as household, nutrition, commercial, and industrial applications, may be termed “non-therapeutic proteins.” Formulations containing non-therapeutic proteins may be termed “non-therapeutic formulations”. The non-therapeutic proteins can be derived from plant sources, animal sources, or produced from cell cultures; they also can be enzymes or structural proteins. The non-therapeutic proteins can be used in in household, nutrition, commercial, and industrial applications such as catalysts, human and animal nutrition, processing aids, cleaners, and waste treatment.

An important category of non-therapeutic biopolymers is enzymes. Enzymes have a number of non-therapeutic applications, for example, as catalysts, human and animal nutritional ingredients, processing aids, cleaners, and waste treatment agents. Enzyme catalysts are used to accelerate a variety of chemical reactions. Examples of enzyme catalysts for non-therapeutic uses include catalases, oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases. Human and animal nutritional uses of enzymes include nutraceuticals, nutritive sources of protein, chelation or controlled delivery of micronutrients, digestion aids, and supplements; these can be derived from amylase, protease, trypsin, lactase, and the like. Enzymatic processing aids are used to improve the production of food and beverage products in operations like baking, brewing, fermenting, juice processing, and winemaking. Examples of these food and beverage processing aids include amylases, cellulases, pectinases, glucanases, lipases, and lactases. Enzymes can also be used in the production of biofuels. Ethanol for biofuels, for example, can be aided by the enzymatic degradation of biomass feedstocks such as cellulosic and lignocellulosic materials. The treatment of such feedstock materials with cellulases and ligninases transforms the biomass into a substrate that can be fermented into fuels. In other commercial applications, enzymes are used as detergents, cleaners, and stain lifting aids for laundry, dish washing, surface cleaning, and equipment cleaning applications. Typical enzymes for this purpose include proteases, cellulases, amylases, and lipases. In addition, non-therapeutic enzymes are used in a variety of commercial and industrial processes such as textile softening with cellulases, leather processing, waste treatment, contaminated sediment treatment, water treatment, pulp bleaching, and pulp softening and debonding. Typical enzymes for these purposes are amylases, xylanases, cellulases, and ligninases.

Other examples of non-therapeutic biopolymers include fibrous or structural proteins such as keratins, collagen, gelatin, elastin, fibroin, actin, tubulin, or the hydrolyzed, degraded, or derivatized forms thereof. These materials are used in the preparation and formulation of food ingredients such as gelatin, ice cream, yogurt, and confections; they area also added to foods as thickeners, rheology modifiers, mouthfeel improvers, and as a source of nutritional protein. In the cosmetics and personal care industry, collagen, elastin, keratin, and hydrolyzed keratin are widely used as ingredients in skin care and hair care formulations. Still other examples of non-therapeutic biopolymers are whey proteins such as beta-lactoglobulin, alpha-lactalbumin, and serum albumin. These whey proteins are produced in mass scale as a byproduct from dairy operations and have been used for a variety of non-therapeutic applications.

2. Therapeutic Formulations

In one aspect, the formulations and methods disclosed herein provide stable liquid formulations of improved or reduced viscosity, comprising a therapeutic protein in a therapeutically effective amount and an excipient compound. In embodiments, the formulation can improve the stability while providing an acceptable concentration of active ingredients and an acceptable viscosity. In embodiments, the formulation provides an improvement in stability when compared to a control formulation; for the purposes of this disclosure, a control formulation is a formulation containing the protein active ingredient that is identical on a dry weight basis in every way to the therapeutic formulation except that it lacks the excipient compound. In embodiments, improved stability of the protein containing formulation is in the form of lower percentage of soluble aggregates, particulates, subvisible particles, or gel formation, compared to a control formulation.

It is understood that the viscosity of a liquid protein formulation can be affected by a variety of factors, including but not limited to: the nature of the protein itself (e.g., enzyme, antibody, receptor, fusion protein, etc.); its size, three-dimensional structure, chemical composition, and molecular weight; its concentration in the formulation; the components of the formulation besides the protein; the desired pH range; the storage conditions for the formulation; and the method of administering the formulation to the patient. Therapeutic proteins most suitable for use with the excipient compounds described herein are preferably essentially pure, i.e., free from contaminating proteins. In embodiments, an “essentially pure” therapeutic protein is a protein composition comprising at least 90% by weight of the therapeutic protein, or preferably at least 95% by weight, or more preferably, at least 99% by weight, all based on the total weight of therapeutic proteins and contaminating proteins in the composition. For the purposes of clarity, a protein added as an excipient is not intended to be included in this definition. The therapeutic formulations described herein are intended for use as pharmaceutical-grade formulations, i.e., formulations intended for use in treating a mammal, in such a form that the desired therapeutic efficacy of the protein active ingredient can be achieved, and without containing components that are toxic to the mammal to whom the formulation is to be administered.

In embodiments, the therapeutic formulation contains at least 25 mg/mL of protein active ingredient. In other embodiments, the therapeutic formulation contains at least 100 mg/mL of protein active ingredient. In other embodiments, the therapeutic formulation contains at least 200 mg/mL of protein active ingredient. In yet other embodiments, the therapeutic formulation solution contains at least 300 mg/mL of protein active ingredient. Generally, the excipient compounds disclosed herein are added to the therapeutic formulation in an amount between about 5 to about 300 mg/mL. In embodiments, the excipient compound can be added in an amount of about 10 to about 200 mg/mL. In embodiments, the excipient compound can be added in an amount of about 20 to about 100 mg/mL. In embodiments, the excipient can be added in an amount of about 25 to about 75 mg/mL.

Excipient compounds of various molecular weights are selected for specific advantageous properties when combined with the protein active ingredient in a formulation. Examples of therapeutic formulations comprising excipient compounds are provided below. In embodiments, the excipient compound has a molecular weight of <5000 Da. In embodiments, the excipient compound has a molecular weight of <1000 Da. In embodiments, the excipient compound has a molecular weight of <500 Da.

In embodiments, the excipient compounds disclosed herein is added to the therapeutic formulation in a viscosity-reducing amount. In embodiments, a viscosity-reducing amount is the amount of an excipient compound that reduces the viscosity of the formulation at least 10% when compared to a control formulation; for the purposes of this disclosure, a control formulation is a formulation containing the protein active ingredient that is identical on a dry weight basis in every way to the therapeutic formulation except that it lacks the excipient compound. In embodiments, the viscosity-reducing amount is the amount of an excipient compound that reduces the viscosity of the formulation at least 30% when compared to the control formulation. In embodiments, the viscosity-reducing amount is the amount of an excipient compound that reduces the viscosity of the formulation at least 50% when compared to the control formulation. In embodiments, the viscosity-reducing amount is the amount of an excipient compound that reduces the viscosity of the formulation at least 70% when compared to the control formulation. In embodiments, the viscosity-reducing amount is the amount of an excipient compound that reduces the viscosity of the formulation at least 90% when compared to the control formulation.

In embodiments, the viscosity-reducing amount yields a therapeutic formulation having a viscosity of less than 100 cP. In other embodiments, the therapeutic formulation has a viscosity of less than 50 cP. In other embodiments, the therapeutic formulation has a viscosity of less than 20 cP. In yet other embodiments, the therapeutic formulation has a viscosity of less than 10 cP. The term “viscosity” as used herein refers to a dynamic viscosity value when measured by the methods disclosed herein.

Therapeutic formulations in accordance with this disclosure have certain advantageous properties. In embodiments, the therapeutic formulations are resistant to shear degradation, phase separation, clouding out, precipitation, and denaturing. In embodiments, the therapeutic formulations are processed, purified, stored, syringed, dosed, filtered, and centrifuged more effectively, compared with a control formulation. In embodiments, the therapeutic formulations are administered to a patient at high concentration of therapeutic protein. In embodiments, the therapeutic formulations are administered to patients with less discomfort than would be experienced with a similar formulation lacking the therapeutic excipient. In embodiments, the therapeutic formulations are administered as a depot injection. In embodiments, the therapeutic formulations extend the half-life of the therapeutic protein in the body. These features of therapeutic formulations as disclosed herein would permit the administration of such formulations by intramuscular or subcutaneous injection in a clinical situation, i.e., a situation where patient acceptance of an intramuscular injection would include the use of small-bore needles typical for IM/SC purposes and the use of a tolerable (for example, 2-3 cc) injected volume, and where these conditions result in the administration of an effective amount of the formulation in a single injection at a single injection site. By contrast, injection of a comparable dosage amount of the therapeutic protein using conventional formulation techniques would be limited by the higher viscosity of the conventional formulation, so that a SC/IM injection of the conventional formulation would not be suitable for a clinical situation.

In embodiments, the therapeutic excipient has antioxidant properties that stabilize the therapeutic protein against oxidative damage. In embodiments, the therapeutic formulation is stored at ambient temperatures, or for extended time at refrigerator conditions without appreciable loss of potency for the therapeutic protein. In embodiments, the therapeutic formulation is dried down for storage until it is needed; then it is reconstituted with an appropriate solvent, e.g., water. Advantageously, the formulations prepared as described herein can be stable over a prolonged period of time, from months to years. When exceptionally long periods of storage are desired, the formulations can be preserved in a freezer (and later reactivated) without fear of protein denaturation. In embodiments, formulations can be prepared for long-term storage that do not require refrigeration.

Methods for preparing therapeutic formulations may be familiar to skilled artisans. The therapeutic formulations of the present invention can be prepared, for example, by adding the excipient compound to the formulation before or after the therapeutic protein is added to the solution. The therapeutic formulation can, for example, be produced by combining the therapeutic protein and the excipient at a first (lower) concentration and then processed by filtration or centrifugation to produce a second (higher) concentration of the therapeutic protein. Therapeutic formulations can be made with one or more of the excipient compounds with chaotropes, kosmotropes, hydrotropes, and salts. Therapeutic formulations can be made with one or more of the excipient compounds using techniques such as encapsulation, dispersion, liposome, vesicle formation, and the like. Methods for preparing therapeutic formulations comprising the excipient compounds disclosed herein can include combinations of the excipient compounds. In embodiments, combinations of excipients can produce benefits in lower viscosity, improved stability, or reduced injection site pain. Other additives may be introduced into the therapeutic formulations during their manufacture, including preservatives, surfactants, sugars, sucrose, trehalose, polysaccharides, arginine, proline, hyaluronidase, stabilizers, buffers, and the like. As used herein, a pharmaceutically acceptable excipient compound is one that is non-toxic and suitable for animal and/or human administration.

3. Non-Therapeutic Formulations

In one aspect, the formulations and methods disclosed herein provide stable liquid formulations of improved or reduced viscosity, comprising a non-therapeutic protein in an effective amount and an excipient compound. In embodiments, the formulation improves the stability while providing an acceptable concentration of active ingredients and an acceptable viscosity. In embodiments, the formulation provides an improvement in stability when compared to a control formulation; for the purposes of this disclosure, a control formulation is a formulation containing the protein active ingredient that is identical on a dry weight basis in every way to the non-therapeutic formulation except that it lacks the excipient compound.

It is understood that the viscosity of a liquid protein formulation can be affected by a variety of factors, including but not limited to: the nature of the protein itself (e.g., enzyme, structural protein, degree of hydrolysis, etc.); its size, three-dimensional structure, chemical composition, and molecular weight; its concentration in the formulation; the components of the formulation besides the protein; the desired pH range; and the storage conditions for the formulation.

In embodiments, the non-therapeutic formulation contains at least 25 mg/mL of protein active ingredient. In other embodiments, the non-therapeutic formulation contains at least 100 mg/mL of protein active ingredient. In other embodiments, the non-therapeutic formulation contains at least 200 mg/mL of protein active ingredient. In yet other embodiments, the non-therapeutic formulation solution contains at least 300 mg/mL of protein active ingredient.

Generally, the excipient compounds disclosed herein are added to the non-therapeutic formulation in an amount between about 5 to about 300 mg/mL. In embodiments, the excipient compound is added in an amount of about 10 to about 200 mg/mL. In embodiments, the excipient compound is added in an amount of about 20 to about 100 mg/mL. In embodiments, the excipient is added in an amount of about 25 to about 75 mg/mL.

Excipient compounds of various molecular weights are selected for specific advantageous properties when combined with the protein active ingredient in a formulation. Examples of non-therapeutic formulations comprising excipient compounds are provided below. In embodiments, the excipient compound has a molecular weight of <5000 Da. In embodiments, the excipient compound has a molecular weight of <1000 Da. In embodiments, the excipient compound has a molecular weight of <500 Da.

In embodiments, the excipient compounds disclosed herein is added to the non-therapeutic formulation in a viscosity-reducing amount. In embodiments, a viscosity-reducing amount is the amount of an excipient compound that reduces the viscosity of the formulation at least 10% when compared to a control formulation; for the purposes of this disclosure, a control formulation is a formulation containing the protein active ingredient that is identical on a dry weight basis in every way to the therapeutic formulation except that it lacks the excipient compound. In embodiments, the viscosity-reducing amount is the amount of an excipient compound that reduces the viscosity of the formulation at least 30% when compared to the control formulation. In embodiments, the viscosity-reducing amount is the amount of an excipient compound that reduces the viscosity of the formulation at least 50% when compared to the control formulation. In embodiments, the viscosity-reducing amount is the amount of an excipient compound that reduces the viscosity of the formulation at least 70% when compared to the control formulation. In embodiments, the viscosity-reducing amount is the amount of an excipient compound that reduces the viscosity of the formulation at least 90% when compared to the control formulation.

In embodiments, the viscosity-reducing amount yields a non-therapeutic formulation having a viscosity of less than 100 cP. In other embodiments, the non-therapeutic formulation has a viscosity of less than 50 cP. In other embodiments, the non-therapeutic formulation has a viscosity of less than 20 cP. In yet other embodiments, the non-therapeutic formulation has a viscosity of less than 10 cP. The term “viscosity” as used herein refers to a dynamic viscosity value.

Non-therapeutic formulations in accordance with this disclosure can have certain advantageous properties. In embodiments, the non-therapeutic formulations are resistant to shear degradation, phase separation, clouding out, precipitation, and denaturing. In embodiments, the therapeutic formulations can be processed, purified, stored, pumped, filtered, and centrifuged more effectively, compared with a control formulation.

In embodiments, the non-therapeutic excipient has antioxidant properties that stabilize the non-therapeutic protein against oxidative damage. In embodiments, the non-therapeutic formulation is stored at ambient temperatures, or for extended time at refrigerator conditions without appreciable loss of potency for the non-therapeutic protein. In embodiments, the non-therapeutic formulation is dried down for storage until it is needed; then it can be reconstituted with an appropriate solvent, e.g., water. Advantageously, the formulations prepared as described herein is stable over a prolonged period of time, from months to years. When exceptionally long periods of storage are desired, the formulations are preserved in a freezer (and later reactivated) without fear of protein denaturation. In embodiments, formulations are prepared for long-term storage that do not require refrigeration.

Methods for preparing non-therapeutic formulations comprising the excipient compounds disclosed herein may be familiar to skilled artisans. For example, the excipient compound can be added to the formulation before or after the non-therapeutic protein is added to the solution. The non-therapeutic formulation can be produced at a first (lower) concentration and then processed by filtration or centrifugation to produce a second (higher) concentration. Non-therapeutic formulations can be made with one or more of the excipient compounds with chaotropes, kosmotropes, hydrotropes, and salts. Non-therapeutic formulations can be made with one or more of the excipient compounds using techniques such as encapsulation, dispersion, liposome, vesicle formation, and the like. Other additives can be introduced into the non-therapeutic formulations during their manufacture, including preservatives, surfactants, stabilizers, and the like.

4. Excipient Compounds

Several excipient compounds are described herein, each suitable for use with one or more therapeutic or non-therapeutic proteins, and each allowing the formulation to be composed so that it contains the protein(s) at a high concentration. Some of the categories of excipient compounds described below are: (1) hindered amines; (2) anionic aromatics; (3) functionalized amino acids; and (4) oligopeptides. Without being bound by theory, the excipient compounds described herein are thought to associate with certain fragments, sequences, structures, or sections of a therapeutic protein that otherwise would be involved in inter-particle (i.e., protein-protein) interactions. The association of these excipient compounds with the therapeutic or non-therapeutic protein can mask the inter-protein interactions such that the proteins can be formulated in high concentration without causing excessive solution viscosity. Excipient compounds advantageously can be water-soluble, therefore suitable for use with aqueous vehicles. In embodiments, the excipient compounds have a water solubility of >10 mg/mL. In embodiments, the excipient compounds have a water solubility of >100 mg/mL. In embodiments, the excipient compounds have a water solubility of >500 mg/mL. Advantageously for therapeutic proteins, the excipient compounds can be derived from materials that are biologically acceptable and are non-immunogenic, and are thus suitable for pharmaceutical use. In therapeutic embodiments, the excipient compounds can be metabolized in the body to yield biologically compatible and non-immunogenic byproducts.

a. Excipient Compound Category 1: Hindered Amines

High concentration solutions of therapeutic or non-therapeutic proteins can be formulated with hindered amine small molecules as excipient compounds. As used herein, the term “hindered amine” refers to a small molecule containing at least one bulky or sterically hindered group, consistent with the examples below. Hindered amines can be used in the free base form, in the protonated form, or a combination of the two. In protonated forms, the hindered amines can be associated with an anionic counterion such as chloride, hydroxide, bromide, iodide, fluoride, acetate, formate, phosphate, sulfate, or carboxylate. Hindered amine compounds useful as excipient compounds can contain secondary amine, tertiary amine, quaternary ammonium, pyridinium, pyrrolidone, pyrrolidine, piperidine, morpholine, or guanidinium groups, such that the excipient compound has a cationic charge in aqueous solution at neutral pH. The hindered amine compounds also contain at least one bulky or sterically hindered group, such as cyclic aromatic, cycloaliphatic, cyclohexyl, or alkyl groups. In embodiments, the sterically hindered group can itself be an amine group such as a dialkylamine, trialkylamine, guanidinium, pyridinium, or quaternary ammonium group. Without being bound by theory, the hindered amine compounds are thought to associate with aromatic sections of the proteins such as phenylalanine, tryptophan, and tyrosine, by a cation pi interaction. In embodiments, the cationic group of the hindered amine can have an affinity for the electron rich pi structure of the aromatic amino acid residues in the protein, so that they can shield these sections of the protein, thereby decreasing the tendency of such shielded proteins to associate and agglomerate.

In embodiments, the hindered amine excipient compounds has a chemical structure comprising imidazole, imidazoline, or imidazolidine groups, or salts thereof, such as imidazole, 1-methylimidazole, 4-methylimidazole, 1-hexyl-3-methylimidazolium chloride, histamine, 4-methylhistamine, alpha-methylhistamine, betahistine, beta-alanine, 2-methyl-2-imidazoline, 1-butyl-3-methylimidazolium chloride, uric acid, potassium urate, betazole, carnosine, aspartame, saccharin, acesulfame potassium, xanthine, theophylline, theobromine, caffeine, and anserine. In embodiments, the hindered amine excipient compounds is selected from the group consisting of dimethylethanolamine, dimethylaminopropylamine, triethanolamine, dimethylbenzylamine, dimethylcyclohexylamine, diethylcyclohexylamine, dicyclohexylmethylamine, hexamethylene biguanide, poly(hexamethylene biguanide), imidazole, dimethylglycine, agmatine, diazabicyclo[2.2.2]octane, tetramethylethylenediamine, N,N-dimethylethanolamine, ethanolamine phosphate, glucosamine, choline chloride, phosphocholine, niacinamide, isonicotinamide, N,N-diethyl nicotinamide, nicotinic acid sodium salt, tyramine, 3-aminopyridine, 2,4,6-trimethylpyridine, 3-pyridine methanol, nicotinamide adenosine dinucleotide, biotin, morpholine, N-methylpyrrolidone, 2-pyrrolidinone, procaine, lidocaine, dicyandiamide-taurine adduct, 2-pyridylethylamine, dicyandiamide-benzyl amine adduct, dicyandiamide-alkylamine adduct, dicyandiamide-cycloalkylamine adduct, and dicyandiamide-aminomethanephosphonic acid adducts. In embodiments, a hindered amine compound consistent with this disclosure is formulated as a protonated ammonium salt. In embodiments, a hindered amine compound consistent with this disclosure is formulated as a salt with an inorganic anion or organic anion as the counterion. In embodiments, high concentration solutions of therapeutic or non-therapeutic proteins are formulated with a combination of caffeine with a benzoic acid, a hydroxybenzoic acid, or a benzenesulfonic acid as excipient compounds. In embodiments, the hindered amine excipient compounds is metabolized in the body to yield biologically compatible byproducts. In some embodiments, the hindered amine excipient compound is present in the formulation at a concentration of about 250 mg/ml or less. In additional embodiments, the hindered amine excipient compound is present in the formulation at a concentration of about 10 mg/ml to about 200 mg/ml. In yet additional aspects, the hindered amine excipient compound is present in the formulation at a concentration of about 20 to about 120 mg/ml.

In embodiments, certain hindered amine excipient compounds can possess other pharmacological properties. As examples, xanthines are a category of hindered amines having independent pharmacological properties, including stimulant properties and bronchodilator properties when systemically absorbed. Representative xanthines include caffeine, aminophylline, 3-isobutyl-1-methylxanthine, paraxanthine, pentoxifylline, theobromine, theophylline, and the like. Methylated xanthines are understood to affect force of cardiac contraction, heart rate, and bronchodilation. In some embodiments, the xanthine excipient compound is present in the formulation at a concentration of about 30 mg/ml or less.

Another category of hindered amines having independent pharmacological properties are the local injectable anesthetic compounds. Local injectable anesthetic compounds are hindered amines that have a three-component molecular structure of (a) a lipophilic aromatic ring, (b) an intermediate ester or amide linkage, and (c) a secondary or tertiary amine. This category of hindered amines is understood to interrupt neural conduction by inhibiting the influx of sodium ions, thereby inducing local anesthesia. The lipophilic aromatic ring for a local anesthetic compound may be formed of carbon atoms (e.g., a benzene ring) or it may comprise heteroatoms (e.g., a thiophene ring). Representative local injectable anesthetic compounds include, but are not limited to, amylocaine, articaine, bupivicaine, butacaine, butanilicaine, chlorprocaine, cocaine, cyclomethycaine, dimethocaine, editocaine, hexylcaine, isobucaine, levobupivacaine, lidocaine, metabutethamine, metabutoxycaine, mepivacaine, meprylcaine, propoxycaine, prilocaine, procaine, piperocaine, tetracaine, trimecaine, and the like. The local injectable anesthetic compounds can have multiple benefits in protein therapeutic formulations, such as reduced viscosity, improved stability, and reduced pain upon injection. In some embodiments, the local anesthetic compound is present in the formulation in a concentration of about 50 mg/ml or less.

In embodiments, a hindered amine having independent pharmacological properties is used as an excipient compound in accordance with the formulations and methods described herein. In some embodiments, the excipient compounds possessing independent pharmacological properties are present in an amount that does not have a pharmacological effect and/or that is not therapeutically effective. In other embodiments, the excipient compounds possessing independent pharmacological properties are present in an amount that does have a pharmacological effect and/or that is therapeutically effective. In certain embodiments, a hindered amine having independent pharmacological properties is used in combination with another excipient compound that has been selected to decrease formulation viscosity, where the hindered amine having independent pharmacological properties is used to impart the benefits of its pharmacological activity. For example, a local injectable anesthetic compound can be used to decrease formulation viscosity and also to reduce pain upon injection of the formulation. The reduction of injection pain can be caused by anesthetic properties; also a lower injection force can be required when the viscosity is reduced by the excipients. Alternatively, a local injectable anesthetic compound can be used to impart the desirable pharmacological benefit of decreased local sensation during formulation injection, while being combined with another excipient compound that reduces the viscosity of the formulation.

b. Excipient Compound Category 2: Anionic Aromatics

High concentration solutions of therapeutic or non-therapeutic proteins can be formulated with anionic aromatic small molecule compounds as excipient compounds. The anionic aromatic excipient compounds can contain an aromatic functional group such as phenyl, benzyl, aryl, alkylbenzyl, hydroxybenzyl, phenolic, hydroxyaryl, heteroaromatic group, or a fused aromatic group. The anionic aromatic excipient compounds also can contain an anionic functional group such as carboxylate, oxide, phenoxide, sulfonate, sulfate, phosphonate, phosphate, or sulfide. While the anionic aromatic excipients might be described as an acid, a sodium salt, or other, it is understood that the excipient can be used in a variety of salt forms. Without being bound by theory, an anionic aromatic excipient compound is thought to be a bulky, sterically hindered molecule that can associate with cationic segments of a protein, so that they can shield these sections of the protein, thereby decreasing the interactions between protein molecules that render the protein-containing formulation viscous.

In embodiments, examples of anionic aromatic excipient compounds include compounds such as salicylic acid, aminosalicylic acid, hydroxybenzoic acid, aminobenzoic acid, para-aminobenzoic acid, benzenesulfonic acid, hydroxybenzenesulfonic acid, naphthalenesulfonic acid, naphthalenedisulfonic acid, hydroquinone sulfonic acid, sulfanilic acid, vanillic acid, vanillin, vanillin-taurine adduct, aminophenol, anthranilic acid, cinnamic acid, coumaric acid, adenosine monophosphate, indole acetic acid, potassium urate, furan dicarboxylic acid, furan-2-acrylic acid, 2-furanpropionic acid, sodium phenylpyruvate, sodium hydroxyphenylpyruvate, dihydroxybenzoic acid, trihydroxybenzoic acid, pyrogallol, benzoic acid, and the salts of the foregoing acids. In embodiments, the anionic aromatic excipient compounds is formulated in the ionized salt form. In embodiments, an anionic aromatic compound is formulated as the salt of a hindered amine, such as dimethylcyclohexylammonium hydroxybenzoate. In embodiments, the anionic aromatic excipient compounds is formulated with various counterions such as organic cations. In embodiments, high concentration solutions of therapeutic or non-therapeutic proteins is formulated with anionic aromatic excipient compounds and caffeine. In embodiments, the anionic aromatic excipient compounds is metabolized in the body to yield biologically compatible byproducts.

c. Excipient Compound Category 3: Functionalized Amino Acids

High concentration solutions of therapeutic or non-therapeutic proteins can be formulated with one or more functionalized amino acids, where a single functionalized amino acid or an oligopeptide comprising one or more functionalized amino acids may be used as the excipient compound. In embodiments, the functionalized amino acid compounds comprise molecules (“amino acid precursors”) that can be hydrolyzed or metabolized to yield amino acids. In embodiments, the functionalized amino acids can contain an aromatic functional group such as phenyl, benzyl, aryl, alkylbenzyl, hydroxybenzyl, hydroxyaryl, heteroaromatic group, or a fused aromatic group. In embodiments, the functionalized amino acid compounds can contain esterified amino acids, such as methyl, ethyl, propyl, butyl, benzyl, cycloalkyl, glyceryl, hydroxyethyl, hydroxypropyl, PEG, and PPG esters. In embodiments, the functionalized amino acid compounds are selected from the group consisting of arginine ethyl ester, arginine methyl ester, arginine hydroxyethyl ester, and arginine hydroxypropyl ester. In embodiments, the functionalized amino acid compound is a charged ionic compound in aqueous solution at neutral pH. For example, a single amino acid can be derivatized by forming an ester, like an acetate or a benzoate, and the hydrolysis products would be acetic acid or benzoic acid, both natural materials, plus the amino acid. In embodiments, the functionalized amino acid excipient compounds is metabolized in the body to yield biologically compatible byproducts.

d. Excipient Compound Category 4: Oligopeptides

High concentration solutions of therapeutic or non-therapeutic proteins can be formulated with oligopeptides as excipient compounds. In embodiments, the oligopeptide is designed such that the structure has a charged section and a bulky section. In embodiments, the oligopeptides consist of between 2 and 10 peptide subunits. The oligopeptide can be bi-functional, for example a cationic amino acid coupled to a non-polar one, or an anionic one coupled to a non-polar one. In embodiments, the oligopeptides consist of between 2 and 5 peptide subunits. In embodiments, the oligopeptides are homopeptides such as polyglutamic acid, polyaspartic acid, poly-lysine, poly-arginine, and poly-histidine. In embodiments, the oligopeptides have a net cationic charge. In other embodiments, the oligopeptides are heteropeptides, such as Trp2Lys3. In embodiments, the oligopeptide can have an alternating structure such as an ABA repeating pattern. In embodiments, the oligopeptide can contain both anionic and cationic amino acids, for example, Arg-Glu. Without being bound by theory, the oligopeptides comprise structures that can associate with proteins in such a way that it reduces the intermolecular interactions that lead to high viscosity solutions; for example, the oligopeptide-protein association can be a charge-charge interaction, leaving a somewhat non-polar amino acid to disrupt hydrogen bonding of the hydration layer around the protein, thus lowering viscosity. In some embodiments, the oligopeptide excipient is present in the composition in a concentration of about 50 mg/ml or less.

e. Excipient Compound Category 5: Short-Chain Organic Acids

As used herein, the term “short-chain organic acids” refers to C2-C6 organic acid compounds and the salts, esters, or lactones thereof. This category includes saturated and unsaturated carboxylic acids, hydroxy functionalized carboxylic acids, and linear, branched, or cyclic carboxylic acids. In embodiments, the acid group in the short-chain organic acid is a carboxylic acid, sulfonic acid, phosphonic acid, or a salt thereof.

In addition to the four excipient categories above, high concentration solutions of therapeutic or non-therapeutic proteins can be formulated with short-chain organic acids, for example, the acid or salt forms of sorbic acid, valeric acid, propionic acid, caproic acid, and ascorbic acid as excipient compounds. Examples of excipient compounds in this category include potassium sorbate, taurine, calcium propionate, magnesium propionate, and sodium ascorbate.

f. Excipient Compound Category 6: Low Molecular Weight Aliphatic Polyacids

High concentration solutions of therapeutic or non-therapeutic PEGylated proteins can be formulated with certain excipient compounds that enable lower solution viscosity, where such excipient compounds are low molecular weight aliphatic polyacids. As used herein, the term “low molecular weight aliphatic polyacids” refers to organic aliphatic polyacids having a molecular weight<about 1500, and having at least two acidic groups, where an acidic group is understood to be a proton-donating moiety. Non-limiting examples of acidic groups include carboxylate, phosphonate, phosphate, sulfonate, sulfate, nitrate, and nitrite groups. Acidic groups on the low molecular weight aliphatic polyacid can be in the anionic salt form such as carboxylate, phosphonate, phosphate, sulfonate, sulfate, nitrate, and nitrite; their counterions can be sodium, potassium, lithium, and ammonium. Specific examples of low molecular weight aliphatic polyacids useful for interacting with PEGylated proteins as described herein include maleic acid, tartaric acid, glutaric acid, malonic acid, citric acid, ethylenediaminetetraacetic acid (EDTA), aspartic acid, glutamic acid, alendronic acid, etidronic acid and salts thereof. Further examples of low molecular weight aliphatic polyacids in their anionic salt form include phosphate (PO4³⁻), hydrogen phosphate (HPO₄ ³⁻), dihydrogen phosphate (H₂PO₄ ⁻), sulfate (SO4²⁻), bisulfate (HSO₄ ⁻), pyrophosphate (P₂O₇ ⁴⁻), carbonate (CO₃ ²⁻), and bicarbonate (HCO₃ ⁻). The counterion for the anionic salts can be Na, Li, K, or ammonium ion. These excipients can also be used in combination with excipients. As used herein, the low molecular weight aliphatic polyacid can also be an alpha hydroxy acid, where there is a hydroxyl group adjacent to a first acidic group, for example glycolic acid, lactic acid, and gluconic acid and salts thereof. In embodiments, the low molecular weight aliphatic polyacid is an oligomeric form that bears more than two acidic groups, for example polyacrylic acid, polyphosphates, polypeptides and salts thereof. In some embodiments, the low molecular weight aliphatic polyacid excipient is present in the composition in a concentration of about 50 mg/ml or less.

5. Protein/Excipient Solutions: Properties and Processes

In certain embodiments, solutions of therapeutic or non-therapeutic proteins is formulated with the above-identified excipient compounds, such as hindered amines, anionic aromatics, functionalized amino acids, oligopeptides, short-chain organic acids to result in an improved protein-protein interaction characteristics as measured by the protein diffusion interaction parameter, kD, or the second virial coefficient, B22. As used herein, an “improvement” in protein-protein interaction characteristics achieved by formulations using the above-identified excipient compounds means a decrease in protein-protein interactions. These measurements of kD and B22 can be made using standard techniques in the industry, and can be an indicator of improved solution properties or stability of the protein in solution. For example, a highly negative kD value can indicate that the protein has a strong attractive interaction and this can lead to aggregation, instability, and rheology problems. When formulated in the presence of certain of the above identified excipient compounds, the same protein can have a less negative kD value, or a kD value near or above zero.

In embodiments, certain of the above-described excipient compounds, such as hindered amines, anionic aromatics, functionalized amino acids, oligopeptides, short-chain organic acids, and/or low molecular weight aliphatic polyacids are used to improve a protein-related process, such as the manufacture, processing, sterile filling, purification, and analysis of protein-containing solutions, using processing methods such as filtration, syringing, transferring, pumping, mixing, heating or cooling by heat transfer, gas transfer, centrifugation, chromatography, membrane separation, centrifugal concentration, tangential flow filtration, radial flow filtration, axial flow filtration, lyophilization, and gel electrophoresis. These processes and processing methods can have improved efficiency due to the lower viscosity, improved solubility, or improved stability of the proteins in the solution during manufacture, processing, purification, and analysis steps. Additionally, equipment-related processes such as the cleanup, sterilization, and maintenance of protein processing equipment can be facilitated by the use of the above-identified excipients due to decreased fouling, decreased denaturing, lower viscosity, and improved solubility of the protein.

High concentration solutions of therapeutic proteins formulated with the above described excipient compounds can be administered to patients using pre-filled syringes.

EXAMPLES

Materials:

-   -   Bovine gamma globulin (BGG), >99% purity, Sigma Aldrich     -   Histidine, Sigma Aldrich     -   Other materials described in the examples below were from Sigma         Aldrich unless otherwise specified.

Example 1 Preparation of Formulations Containing Excipient Compounds and Test Protein

Formulations were prepared using an excipient compound and a test protein, where the test protein was intended to simulate either a therapeutic protein that would be used in a therapeutic formulation, or a non-therapeutic protein that would be used in a non-therapeutic formulation. Such formulations were prepared in 50 mM histidine hydrochloride with different excipient compounds for viscosity measurement in the following way. Histidine hydrochloride was first prepared by dissolving 1.94 g histidine (Sigma-Aldrich, St. Louis, Mo.) in distilled water and adjusting the pH to about 6.0 with 1 M hydrochloric acid (Sigma-Aldrich, St. Louis, Mo.) and then diluting to a final volume of 250 mL with distilled water in a volumetric flask. Excipient compounds were then dissolved in 50 mM histidine HCl. Lists of excipients are provided below in Examples 4, 5, 6, and 7. In some cases excipient compounds were adjusted to pH 6 prior to dissolving in 50 mM histidine HCl. In this case the excipient compounds were first dissolved in deionized water at about 5 wt % and the pH was adjusted to about 6.0 with either hydrochloric acid or sodium hydroxide. The prepared salt solution was then placed in a convection laboratory oven at about 150 degrees Fahrenheit (about 65 degrees C.) to evaporate the water and isolate the solid excipient. Once excipient solutions in 50 mM histidine HCl had been prepared, the test protein (bovine gamma globulin (BGG) (Sigma-Aldrich, St. Louis, Mo.)) was dissolved at a ratio of about 0.336 g BGG per 1 mL excipient solution. This resulted in a final protein concentration of about 280 mg/mL. Solutions of BGG in 50 mM histidine HCl with excipient were formulated in 20 mL vials and allowed to shake at 100 rpm on an orbital shaker table overnight. BGG solutions were then transferred to 2 mL microcentrifuge tubes and centrifuged for ten minutes at 2300 rpm in an IEC MicroMax microcentrifuge to remove entrained air prior to viscosity measurement.

Example 2 Viscosity Measurement

Viscosity measurements of formulations prepared as described in Example 1 were made with a DV-IIT LV cone and plate viscometer (Brookfield Engineering, Middleboro, Mass.). The viscometer was equipped with a CP-40 cone and was operated at 3 rpm and 25 degrees C. The formulation was loaded into the viscometer at a volume of 0.5 mL and allowed to incubate at the given shear rate and temperature for 3 minutes, followed by a measurement collection period of twenty seconds. This was then followed by 2 additional steps consisting of 1 minute of shear incubation and subsequent twenty-second measurement collection period. The three data points collected were then averaged and recorded as the viscosity for the sample.

Example 3 Protein Concentration Measurement

The concentration of the protein in the experimental solutions was determined by measuring the absorbance of the protein solution at a wavelength of 280 nm in a UV/VIS Spectrometer (Perkin Elmer Lambda 35). First the instrument was calibrated to zero absorbance with a 50 mM histidine buffer at pH 6. Next the protein solutions were diluted by a factor of 300 with the same histidine buffer and the absorbance at 280 nm recorded. The final concentration of the protein in the solution was calculated by using the extinction coefficient value of 1.264 mL/(mg×cm).

Example 4 Formulations with Hindered Amine Excipient Compounds

Formulations containing 280 mg/mL BGG were prepared as described in Example 1, with some samples containing added excipient compounds. In these tests, the hydrochloride salts of dimethylcyclohexylamine (DMCHA), dicyclohexylmethylamine (DCHMA), dimethylaminopropylamine (DMAPA), triethanolamine (TEA), dimethylethanolamine (DMEA), and niacinamide were tested as examples of the hindered amine excipient compounds. Also a hydroxybenzoic acid salt of DMCHA and a taurine-dicyandiamide adduct were tested as examples of the hindered amine excipient compounds. The viscosity of each protein solution was measured as described in Example 2, and the results are presented in Table 1 below, showing the benefit of the added excipient compounds in reducing viscosity.

TABLE 1 Excipient Vis- Vis- Test Concentration cosity cosity Number Excipient Added (mg/mL) (cP) Reduction 4.1 None 0 79  0% 4.2 DMCHA-HCl 28 50 37% 4.3 DMCHA-HCl 41 43 46% 4.4 DMCHA-HCl 50 45 43% 4.5 DMCHA-HCl 82 36 54% 4.6 DMCHA-HCl 123 35 56% 4.7 DMCHA-HCl 164 40 49% 4.8 DMAPA-HCl 87 57 28% 4.9 DMAPA-HCl 40 54 32% 4.10 DCHMA-HCl 29 51 35% 4.11 DCHMA-HCl 50 51 35% 4.14 TEA-HCl 97 51 35% 4.15 TEA-HCl 38 57 28% 4.16 DMEA-HCl 51 51 35% 4.17 DMEA-HCl 98 47 41% 4.20 DMCHA-hydroxybenzoate 67 46 42% 4.21 DMCHA-hydroxybenzoate 92 42 47% 4.22 Product of Example 8 26 58 27% 4.23 Product of Example 8 58 50 37% 4.24 Product of Example 8 76 49 38% 4.25 Product of Example 8 103 46 42% 4.26 Product of Example 8 129 47 41% 4.27 Product of Example 8 159 42 47% 4.28 Product of Example 8 163 42 47% 4.29 Niacinamide 48 39 51% 4.30 N-Methyl-2-pyrrolidone 30 45 43% 4.31 N-Methyl-2-pyrrolidone 52 52 34%

Example 5 Formulations with Anionic Aromatic Excipient Compounds

Formulations of 280 mg/mL BGG were prepared as described in Example 1, with some samples containing added excipient compounds. The viscosity of each solution was measured as described in Example 2, and the results are presented in Table 2 below, showing the benefit of the added excipient compounds in reducing viscosity.

TABLE 2 Excipient Vis- Vis- Test Concentration cosity cosity Number Excipient Added (mg/mL) (cP) Reduction 5.1 None 0 79  0% 5.2 Sodium aminobenzoate 43 48 39% 5.3 Sodium hydroxybenzoate 26 50 37% 5.4 Sodium sulfanilate 44 49 38% 5.5 Sodium sulfanilate 96 42 47% 5.6 Sodium indole acetate 52 58 27% 5.7 Sodium indole acetate 27 78  1% 5.8 Vanillic acid, sodium salt 25 56 29% 5.9 Vanillic acid, sodium salt 50 50 37% 5.10 Sodium salicylate 25 57 28% 5.11 Sodium salicylate 50 52 34% 5.12 Adenosine monophosphate 26 47 41% 5.13 Adenosine monophosphate 50 66 16% 5.14 Sodium benzoate 31 61 23% 5.15 Sodium benzoate 56 62 22%

Example 6 Formulations with Oligopeptide Excipient Compounds

Oligopeptides (n=5) were synthesized by NeoBioLab Inc. in >95% purity with the N terminus as a free amine and the C terminus as a free acid. Dipeptides (n=2) were synthesized by LifeTein LLC in 95% purity. Formulations of 280 mg/mL BGG were prepared as described in Example 1, with some samples containing the synthetic oligopeptides as added excipient compounds. The viscosity of each solution was measured as described in Example 2, and the results are presented in Table 3 below, showing the benefit of the added excipient compounds in reducing viscosity.

TABLE 3 Excipient Concentra- Test tion Viscosity Viscosity Number Excipient Added (mg/mL) (cP) Reduction 6.1 None 0 79 0% 6.2 ArgX5 100 55 30% 6.3 ArgX5 50 54 32% 6.4 HisX5 100 62 22% 6.5 HisX5 50 51 35% 6.6 HisX5 25 60 24% 6.7 Trp2Lys3 100 59 25% 6.8 Trp2Lys3 50 60 24% 6.9 AspX5 100 102 −29% 6.10 AspX5 50 82 −4% 6.11 Dipeptide LE (Leu-Glu) 50 72 9% 6.12 Dipeptide YE (Tyr-Glu) 50 55 30% 6.13 Dipeptide RP (Arg-Pro) 50 51 35% 6.14 Dipeptide RK (Arg-Lys) 50 53 33% 6.15 Dipeptide RH (Arg-His) 50 52 34% 6.16 Dipeptide RR (Arg-Arg) 50 57 28% 6.17 Dipeptide RE (Arg-Glu) 50 50 37% 6.18 Dipeptide LE (Leu-Glu) 100 87 −10% 6.19 Dipeptide YE (Tyr-Glu) 100 68 14% 6.20 Dipeptide RP (Arg-Pro) 100 53 33% 6.21 Dipeptide RK (Arg-Lys) 100 64 19% 6.22 Dipeptide RH (Arg-His) 100 72 9% 6.23 Dipeptide RR (Arg-Arg) 100 62 22% 6.24 Dipeptide RE (Arg-Glu) 100 66 16%

Example 8 Synthesis of Guanyl Taurine Excipient

Guanyl taurine was prepared following method described in U.S. Pat. No. 2,230,965. Taurine (Sigma-Aldrich, St. Louis, Mo.) 3.53 parts were mixed with 1.42 parts of dicyandiamide (Sigma-Aldrich, St. Louis, Mo.) and grinded in a mortar and pestle until a homogeneous mixture was obtained. Next the mixture was placed in a flask and heated at 200° C. for 4 hours. The product was used without further purification.

Example 9 Protein Formulations Containing Excipient Compounds

Formulations were prepared using an excipient compound and a test protein, where the test protein was intended to simulate either a therapeutic protein that would be used in a therapeutic formulation, or a non-therapeutic protein that would be used in a non-therapeutic formulation. Such formulations were prepared in 50 mM aqueous histidine hydrochloride buffer solution with different excipient compounds for viscosity measurement in the following way. Histidine hydrochloride buffer solution was first prepared by dissolving 1.94 g histidine (Sigma-Aldrich, St. Louis, Mo.) in distilled water and adjusting the pH to about 6.0 with 1 M hydrochloric acid (Sigma-Aldrich, St. Louis, Mo.) and then diluting to a final volume of 250 mL with distilled water in a volumetric flask. Excipient compounds were then dissolved in the 50 mM histidine HCl buffer solution. A list of the excipient compounds is provided in Table 4. In some cases excipient compounds were dissolved in 50 mM histidine HCl and the resulting solution pH was adjusted with small amounts of concentrated sodium hydroxide or hydrochloric acid to achieve pH 6 prior to dissolution of the model protein. In some cases excipient compounds were adjusted to pH 6 prior to dissolving in 50 mM histidine HCl. In this case the excipient compounds were first dissolved in deionized water at about 5 wt % and the pH was adjusted to about 6.0 with either hydrochloric acid or sodium hydroxide. The prepared salt solution was then placed in a convection laboratory oven at about 150 degrees Fahrenheit (65 degrees C.) to evaporate the water and isolate the solid excipient. Once excipient solutions in 50 mM histidine HCl had been prepared, the test protein, bovine gamma globulin (Sigma-Aldrich, St. Louis, Mo.) was dissolved at a ratio to achieve a final protein concentration of about 280 mg/mL. Solutions of BGG in 50 mM histidine HCl with excipient were formulated in 20 mL vials and allowed to shake at 100 rpm on an orbital shaker table overnight. BGG solutions were then transferred to 2 mL microcentrifuge tubes and centrifuged for ten minutes at 2300 rpm in an IEC MicroMax microcentrifuge to remove entrained air prior to viscosity measurement.

Viscosity measurements of formulations prepared as described above were made with a DV-IIT LV cone and plate viscometer (Brookfield Engineering, Middleboro, Mass.). The viscometer was equipped with a CP-40 cone and was operated at 3 rpm and 25 degrees C. The formulation was loaded into the viscometer at a volume of 0.5 mL and allowed to incubate at the given shear rate and temperature for 3 minutes, followed by a measurement collection period of twenty seconds. This was then followed by 2 additional steps consisting of 1 minute of shear incubation and subsequent twenty-second measurement collection period. The three data points collected were then averaged and recorded as the viscosity for the sample. Viscosities of solutions with excipient were normalized to the viscosity of the model protein solution without excipient. The normalized viscosity is the ratio of the viscosity of the model protein solution with excipient to the viscosity of the model protein solution with no excipient.

TABLE 4 Excipient Normalized Test Concentration Viscosity Viscosity Number Excipient Added (mg/mL) (cP) Reduction 9.1 DMCHA-HCl 120 0.44 56% 9.2 Niacinamide 50 0.51 49% 9.3 Isonicotinamide 50 0.48 52% 9.4 Tyramine HCl 70 0.41 59% 9.5 Histamine HCl 50 0.41 59% 9.6 Imidazole HCl 100 0.43 57% 9.7 2-methyl-2- 60 0.43 57% imidazoline HCl 9.8 1-butyl-3- 100 0.48 52% methylimidazolium chloride 9.9 Procaine HCl 50 0.53 47% 9.10 3-aminopyridine 50 0.51 49% 9.11 2,4,6- 50 0.49 51% trimethylpyridine 9.12 3-pyridine methanol 50 0.53 47% 9.13 Nicotinamide 20 0.56 44% adenine dinucleotide 9.15 Sodium 55 0.57 43% phenylpyruvate 9.16 2-Pyrrolidinone 60 0.68 32% 9.17 Morpholine HCl 50 0.60 40% 9.18 Agmatine sulfate 55 0.77 23% 9.19 1-butyl-3- 60 0.66 34% methylimidazolium iodide 9.21 L-Anserine nitrate 50 0.79 21% 9.22 1-hexyl-3- 65 0.89 11% methylimidazolium chloride 9.23 N,N-diethyl 50 0.67 33% nicotinamide 9.24 Nicotinic acid, 100 0.54 46% sodium salt 9.25 Biotin 20 0.69 31%

Example 10 Preparation of Formulations Containing Excipient Combinations and Test Protein

Formulations were prepared using a primary excipient compound, a secondary excipient compound and a test protein, where the test protein was intended to simulate either a therapeutic protein that would be used in a therapeutic formulation, or a non-therapeutic protein that would be used in a non-therapeutic formulation. The primary excipient compounds were selected from compounds having both anionic and aromatic functionality, as listed below in Table 5. The secondary excipient compounds were selected from compounds having either nonionic or cationic charge at pH 6 and either imidazoline or benzene rings, as listed below in Table 5. Formulations of these excipients were prepared in 50 mM histidine hydrochloride buffer solution for viscosity measurement in the following way. Histidine hydrochloride was first prepared by dissolving 1.94 g histidine (Sigma-Aldrich, St. Louis, Mo.) in distilled water and adjusting the pH to about 6.0 with 1 M hydrochloric acid (Sigma-Aldrich, St. Louis, Mo.) and then diluting to a final volume of 250 mL with distilled water in a volumetric flask. The individual primary or secondary excipient compounds were then dissolved in 50 mM histidine HCl. Combinations of primary and secondary excipients were dissolved in 50 mM histidine HCl and the resulting solution pH adjusted with small amounts of concentrated sodium hydroxide or hydrochloric acid to achieve pH 6 prior to dissolution of the model protein. Once excipient solutions had been prepared as described above, the test protein (bovine gamma globulin (BGG) (Sigma-Aldrich, St. Louis, Mo.) was dissolved into each test solution at a ratio to achieve a final protein concentration of about 280 mg/mL. Solutions of BGG in 50 mM histidine HCl with excipient were formulated in 20 mL vials and allowed to shake at 100 rpm on an orbital shaker table overnight. BGG solutions were then transferred to 2 mL microcentrifuge tubes and centrifuged for ten minutes at 2300 rpm in an IEC MicroMax microcentrifuge to remove entrained air prior to viscosity measurement.

Viscosity measurements of formulations prepared as described above were made with a DV-IIT LV cone and plate viscometer (Brookfield Engineering, Middleboro, Mass.). The viscometer was equipped with a CP-40 cone and was operated at 3 rpm and 25 degrees C. The formulation was loaded into the viscometer at a volume of 0.5 mL and allowed to incubate at the given shear rate and temperature for 3 minutes, followed by a measurement collection period of twenty seconds. This was then followed by 2 additional steps consisting of 1 minute of shear incubation and a subsequent twenty-second measurement collection period. The three data points collected were then averaged and recorded as the viscosity for the sample. Viscosities of solutions with excipient were normalized to the viscosity of the model protein solution without excipient, and summarized in Table 5 below. The normalized viscosity is the ratio of the viscosity of the model protein solution with excipient to the viscosity of the model protein solution with no excipient. The example shows that a combination of primary and secondary excipients can give a better result than a single excipient.

TABLE 5 Primary Excipient Secondary Excipient Test Concentration Concentration Normalized Number Name (mg/mL) Name (mg/mL) Viscosity 10.1 Salicylic Acid 30 None 0 0.79 10.2 Salicylic Acid 25 Imidazole 4 0.59 10.3 4-hydroxybenzoic 30 None 0 0.61 acid 10.4 4-hydroxybenzoic 25 Imidazole 5 0.57 acid 10.5 4-hydroxybenzene 31 None 0 0.59 sulfonic acid 10.6 4-hydroxybenzene 26 Imidazole 5 0.70 sulfonic acid 10.7 4-hydroxybenzene 25 Caffeine 5 0.69 sulfonic acid 10.8 None 0 Caffeine 10 0.73 10.9 None 0 Imidazole 5 0.75

Example 11 Preparation of Formulations Containing Excipient Combinations and Test Protein

Formulations were prepared using a primary excipient compound, a secondary excipient compound and a test protein, where the test protein was intended to simulate a therapeutic protein that would be used in a therapeutic formulation, or a non-therapeutic protein that would be used in a non-therapeutic formulation. The primary excipient compounds were selected from compounds having both anionic and aromatic functionality, as listed below in Table 6. The secondary excipient compounds were selected from compounds having either nonionic or cationic charge at pH 6 and either imidazoline or benzene rings, as listed below in Table 6. Formulations of these excipients were prepared in distilled water for viscosity measurement in the following way. Combinations of primary and secondary excipients were dissolved in distilled water and the resulting solution pH adjusted with small amounts of concentrated sodium hydroxide or hydrochloric acid to achieve pH 6 prior to dissolution of the model protein. Once excipient solutions in distilled water had been prepared, the test protein (bovine gamma globulin (BGG) (Sigma-Aldrich, St. Louis, Mo.)) was dissolved at a ratio to achieve a final protein concentration of about 280 mg/mL. Solutions of BGG in distilled water with excipient were formulated in 20 mL vials and allowed to shake at 100 rpm on an orbital shaker table overnight. BGG solutions were then transferred to 2 mL microcentrifuge tubes and centrifuged for ten minutes at 2300 rpm in an IEC MicroMax microcentrifuge to remove entrained air prior to viscosity measurement.

Viscosity measurements of formulations prepared as described above were made with a DV-IIT LV cone and plate viscometer (Brookfield Engineering, Middleboro, Mass.). The viscometer was equipped with a CP-40 cone and was operated at 3 rpm and 25 degrees C. The formulation was loaded into the viscometer at a volume of 0.5 mL and allowed to incubate at the given shear rate and temperature for 3 minutes, followed by a measurement collection period of twenty seconds. This was then followed by 2 additional steps consisting of 1 minute of shear incubation and a subsequent twenty-second measurement collection period. The three data points collected were then averaged and recorded as the viscosity for the sample. Viscosities of solutions with excipient were normalized to the viscosity of the model protein solution without excipient, and summarized in Table 6 below. The normalized viscosity is the ratio of the viscosity of the model protein solution with excipient to the viscosity of the model protein solution with no excipient. The example shows that a combination of primary and secondary excipients can give a better result than a single excipient.

TABLE 6 Primary Excipient Secondary Excipient Con- Con- centra- centra- Test tion tion Normalized Number Name (mg/mL) Name (mg/mL) Viscosity 11.1 Salicylic 20 None 0 0.96 Acid 11.2 Salicylic 20 Caffeine 5 0.71 Acid 11.3 Salicylic 20 Niacinamide 5 0.76 Acid 11.4 Salicylic 20 Imidazole 5 0.73 Acid

Example 12 Preparation of Formulations Containing Excipient Compounds and PEG

Materials: All materials were purchased from Sigma-Aldrich, St. Louis, Mo. Formulations were prepared using an excipient compound and PEG, where the PEG was intended to simulate a therapeutic PEGylated protein that would be used in a therapeutic formulation. Such formulations were prepared by mixing equal volumes of a solution of PEG with a solution of the excipient. Both solutions were prepared in a Tris buffer consisting of 10 mM Tris, 135 mM NaCl, 1 mM trans-cinnamic acid at pH of 7.3.

The PEG solution was prepared by mixing 3 g of Poly(ethylene oxide) average Mw 1,000,000 (Aldrich Catalog #372781) with 97 g of the Tris buffer solution. The mixture was stirred overnight for complete dissolution.

An example of the excipient solution preparation is as follows: An approximately 80 mg/mL solution of citric acid in the Tris buffer was prepared by dissolving 0.4 g of citric acid (Aldrich cat. #251275) in 5 mL of the Tris buffer solution and adjusted the pH to 7.3 with minimum amount of 10 M NaOH solution.

The PEG excipient solution was prepared by mixing 0.5 mL of the PEG solution with 0.5 mL of the excipient solution and mixed by using a vortex for a few seconds. A control sample was prepared by mixing 0.5 mL of the PEG solution with 0.5 mL of the Tris buffer solution.

Example 13 Viscosity Measurements of Formulations Containing Excipient Compounds and PEG

Viscosity measurements of the formulations prepared were made with a DV-IIT LV cone and plate viscometer (Brookfield Engineering, Middleboro, Mass.). The viscometer was equipped with a CP-40 cone and was operated at 3 rpm and 25 degrees C. The formulation was loaded into the viscometer at a volume of 0.5 mL and allowed to incubate at the given shear rate and temperature for 3 minutes, followed by a measurement collection period of twenty seconds. This was then followed by 2 additional steps consisting of 1 minute of shear incubation and subsequent twenty second measurement collection period. The three data points collected were then averaged and recorded as the viscosity for the sample.

The results presented in Table 7 show the effect of the added excipient compounds in reducing viscosity.

TABLE 7 Excipient Concentra- Test tion Viscosity Viscosity Number Excipient (mg/mL) (cP) Reduction 13.1 None 0 104.8 0% 13.2 Citric acid Na salt 40 56.8 44% 13.3 Citric acid Na salt 20 73.3 28% 13.4 glycerol phosphate 40 71.7 30% 13.5 glycerol phosphate 20 83.9 18% 13.6 Ethylene diamine 40 84.7 17% 13.7 Ethylene diamine 20 83.9 15% 13.8 EDTA/K salt 40 67.1 36% 13.9 EDTA/K salt 20 76.9 27% 13.10 EDTA/Na salt 40 68.1 35% 13.11 EDTA/Na salt 20 77.4 26% 13.12 D-Gluconic acid/K salt 40 80.32 23% 13.13 D-Gluconic acid/K salt 20 88.4 16% 13.14 D-Gluconic acid/Na salt 40 81.24 23% 13.15 D-Gluconic acid/Na salt 20 86.6 17% 13.16 lactic acid/K salt 40 80.42 23% 13.17 lactic acid/K salt 85.1 19% 13.18 lactic acid/Na salt 40 86.55 17% 13.19 lactic acid/Na salt 20 87.2 17% 13.20 etidronic acid/K salt 24 71.91 31% 13.21 etidronic acid/K salt 12 80.5 23% 13.22 etidronic acid/Na salt 24 71.6 32% 13.23 etidronic acid/Na salt 12 79.4 24%

Example 14 Preparation of PEGylated BSA with 1 PEG Chain Per BSA Molecule

To a beaker was added 200 mL of a phosphate buffered saline (Aldrich Cat. #P4417) and 4 g of BSA (Aldrich Cat. #A7906) and mixed with a magnetic bar. Next 400 mg of methoxy polyethylene glycol maleimide, MW=5,000, (Aldrich Cat. #63187) was added. The reaction mixture was allowed to react overnight at room temperature. The following day, 20 drops of HCl 0.1 M were added to stop the reaction. The reaction product was characterized by SDS-Page and SEC which clearly showed the PEGylated BSA. The reaction mixture was placed in an Amicon centrifuge tube with a molecular weight cutoff (MWCO) of 30,000 and concentrated to a few milliliters. Next the sample was diluted 20 times with a histidine buffer, 50 mM at a pH of approximately 6, followed by concentrating until a high viscosity fluid was obtained. The final concentration of the protein solution was obtained by measuring the absorbance at 280 nm and using a coefficient of extinction for the BSA of 0.6678. The results indicated that the final concentration of BSA in the solution was 342 mg/mL.

Example 15 Preparation of PEGylated BSA with Multiple PEG Chains Per BSA Molecule

A 5 mg/mL solution of BSA (Aldrich A7906) in phosphate buffer, 25 mM at pH of 7.2, was prepared by mixing 0.5 g of the BSA with 100 mL of the buffer. Next 1 g of a methoxy PEG propionaldehyde Mw=20,000 (JenKem Technology, Plano, Tex. 75024) was added followed by 0.12 g of sodium cyanoborohydride (Aldrich 156159). The reaction was allowed to proceed overnight at room temperature. The following day the reaction mixture was diluted 13 times with a Tris buffer (10 mM Tris, 135 mM NaCl at pH=7.3) and concentrated using Amicon centrifuge tubes MWCO of 30,000 until a concentration of approximately 150 mg/mL was reached.

Example 16 Preparation of PEGylated Lysozyme with Multiple PEG Chains Per Lysozyme Molecule

A 5 mg/mL solution of lysozyme (Aldrich L6876) in phosphate buffer, 25 mM at pH of 7.2, was prepared by mixing 0.5 g of the lysozyme with 100 mL of the buffer. Next 1 g of a methoxy PEG propionaldehyde Mw=5,000 (JenKem Technology, Plano, Tex. 75024) was added followed by 0.12 g of Sodium cyanoborohydride (Aldrich 156159). The reaction was allowed to proceed overnight at room temperature. The following day the reaction mixture was diluted 49 times with the phosphate buffer, 25 mM at pH of 7.2, and concentrated using Amicon centrifuge tubes MWCO of 30,000. The final concentration of the protein solution was obtained by measuring the absorbance at 280 nm and using a coefficient of extinction for the lysozyme of 2.63. The final concentration of lysozyme in the solution was 140 mg/mL.

Example 17 Effect of Excipients on Viscosity of PEGylated BSA with 1 PEG Chain Per BSA Molecule

Formulations of PEGylated BSA (from Example 14 above) with excipients were prepared by adding 6 or 12 milligrams of the excipient salt to 0.3 mL of the PEGylated BSA solution. The solution was mixed by gently shaking and the viscosity was measured by a RheoSense microVisc equipped with an A10 channel (100 micron depth) at a shear rate of 500 sec-1. The viscometer measurements were completed at ambient temperature.

The results presented in Table 8 shows the effect of the added excipient compounds in reducing viscosity.

TABLE 8 Excipient Concentra- Test tion Viscosity Number Excipient (mg/mL) Viscosity (cP) Reduction 17.1 None 0 228.6 0% 17.2 Alpha-Cyclodextrin 20 151.5 34% sulfated Na salt 17.3 K acetate 40 89.5 60%

Example 18 Effect of Excipients on Viscosity of PEGylated BSA with Multiple PEG Chains Per BSA Molecule

A formulations of PEGylated BSA (from Example 15 above) with citric acid Na salt as excipient was prepared by adding 8 milligrams of the excipient salt to 0.2 mL of the PEGylated BSA solution. The solution was mixed by gently shaking and the viscosity was measured by a RheoSense microVisc equipped with an A10 channel (100 micron depth) at a shear rate of 500 sec-1. The viscometer measurements were completed at ambient temperature. The results presented in Table 9 shows the effect of the added excipient compounds in reducing viscosity.

TABLE 9 Excipient Test Concentration Viscosity Viscosity Number Excipient Added (mg/mL) (cP) Reduction 18.1 None 0 56.8 0% 18.2 Citric acid Na salt 40 43.5 23%

Example 19 Effect of Excipients on Viscosity of PEGylated Lysozyme with Multiple PEG Chains Per Lysozyme Molecule

A formulation of PEGylated lysozyme (from Example 16 above) with potassium acetate as excipient was prepared by adding 6 milligrams of the excipient salt to 0.3 mL of the PEGylated lysozyme solution. The solution was mixed by gently shaking and the viscosity was measured by a RheoSense microVisc equipped with an A10 channel (100 micron depth) at a shear rate of 500 sec-1. The viscometer measurements were completed at ambient temperature. The results presented in the next table shows the benefit of the added excipient compounds in reducing viscosity.

TABLE 10 Excipient Concentration Viscosity Viscosity Test Number Excipient (mg/mL) (cP) Reduction 19.1 None 0 24.6 0% 19.2 K acetate 20 22.6 8%

Example 20 Protein Formulations Containing Excipient Combinations

Formulations were prepared using an excipient compound or a combination of two excipient compounds and a test protein, where the test protein was intended to simulate a therapeutic protein that would be used in a therapeutic formulation. These formulations were prepared in 20 mM histidine buffer with different excipient compounds for viscosity measurement in the following way. Excipient combinations were dissolved in 20 mM histidine (Sigma-Aldrich, St. Louis, Mo.) and the resulting solution pH adjusted with small amounts of concentrated sodium hydroxide or hydrochloric acid to achieve pH 6 prior to dissolution of the model protein. Excipient compounds for this Example are listed below in Table 11. Once excipient solutions had been prepared, the test protein (bovine gamma globulin or “BGG” (Sigma-Aldrich, St. Louis, Mo.)) was dissolved at a ratio to achieve a final protein concentration of about 280 mg/mL. Solutions of BGG in the excipient solutions were formulated in 5 mL sterile polypropylene tubes and allowed to shake at 80-100 rpm on an orbital shaker table overnight. BGG solutions were then transferred to 2 mL microcentrifuge tubes and centrifuged for about ten minutes at 2300 rpm in an IEC MicroMax microcentrifuge to remove entrained air prior to viscosity measurement.

Viscosity measurements of formulations prepared as described above were made with a DV-IIT LV cone and plate viscometer (Brookfield Engineering, Middleboro, Mass.). The viscometer was equipped with a CP-40 cone and was operated at 3 rpm and 25 degrees Centigrade. The formulation was loaded into the viscometer at a volume of 0.5 mL and allowed to incubate at the given shear rate and temperature for 3 minutes, followed by a measurement collection period of twenty seconds. This was then followed by 2 additional steps consisting of 1 minute of shear incubation and subsequent twenty second measurement collection period. The three data points collected were then averaged and recorded as the viscosity for the sample. Viscosities of solutions with excipient were normalized to the viscosity of the model protein solution without excipient, and the results are shown in Table 11 below. The normalized viscosity is the ratio of the viscosity of the model protein solution with excipient to the viscosity of the model protein solution with no excipient.

TABLE 11 Excipient A Excipient B Normal- Conc. Conc. ized Test # Name (mg/mL) Name (mg/mL) Viscosity 20.1 None 0 None 0 1.00 20.2 Aspartame 10 None 0 0.83 Saccharin 60 None 0 0.51 20.4 Acesulfame K 80 None 0 0.44 20.5 Theophylline 10 None 0 0.84 20.6 Saccharin 30 None 0 0.58 20.7 Acesulfame K 40 None 0 0.61 20.8 Caffeine 15 Taurine 15 0.82 20.9 Caffeine 15 Tyramine 15 0.67

Example 21 Protein Formulations Containing Excipients to Reduce Viscosity and Injection Pain

Formulations were prepared using an excipient compound, a second excipient compound, and a test protein, where the test protein was intended to simulate a therapeutic protein that would be used in a therapeutic formulation. The first excipient compound, Excipient A, was selected from a group of compounds having local anesthetic properties. The first excipient, Excipient A and the second excipient, Excipient B are listed in Table 12. These formulations were prepared in 20 mM histidine buffer using Excipient A and Excipient B in the following way, so that their viscosities could be measured. Excipients in the amounts disclosed in Table 12 were dissolved in 20 mM histidine (Sigma-Aldrich, St Louis, Mo.) and the resulting solutions were pH adjusted with small amounts of concentrated sodium hydroxide or hydrochloric acid to achieve pH 6 prior to dissolution of the model protein. Once excipient solutions had been prepared, the test protein (bovine gamma globulin (“BGG”) (Sigma-Aldrich, St. Louis, Mo.)) was dissolved in the excipient solution at a ratio to achieve a final protein concentration of about 280 mg/mL. Solutions of BGG in the excipient solutions were formulated in 5 mL sterile polypropylene tubes and allowed to shake at 80-100 rpm on an orbital shaker table overnight. BGG-excipient solutions were then transferred to 2 mL microcentrifuge tubes and centrifuged for about ten minutes at 2300 rpm in an IEC MicroMax microcentrifuge to remove entrained air prior to viscosity measurement.

Viscosity measurements of the formulations prepared as described above were made with a DV-IIT LV cone and plate viscometer (Brookfield Engineering, Middleboro, Mass.). The viscometer was equipped with a CP-40 cone and was operated at 3 rpm and 25 degrees Centigrade. The formulation was loaded into the viscometer at a volume of 0.5 mL and allowed to incubate at the given shear rate and temperature for 3 minutes, followed by a measurement collection period of twenty seconds. This was then followed by 2 additional steps consisting of 1 minute of shear incubation and subsequent twenty second measurement collection period. The three data points collected were then averaged and recorded as the viscosity for the sample. Viscosities of solutions with excipient were normalized to the viscosity of the model protein solution without excipient, and the results are shown in Table 12 below. The normalized viscosity is the ratio of the viscosity of the model protein solution with excipient to the viscosity of the model protein solution with no excipient.

TABLE 12 Excipient A Excipient B Normal- Conc. Conc. ized Test # Name (mg/mL) Name (mg/mL) Viscosity 21.1 None 0 None 0 1.00 21.2 Lidocaine 45 None 0 0.73 21.3 Lidocaine 23 None 0 0.74 21.4 Lidocaine 10 Caffeine 15 0.71 21.5 Procaine HCl 40 None 0 0.64 21.6 Procaine HCl 20 Caffeine 15 0.69

Example 22 Formulations Containing Excipient Compounds and PEG

Formulations were prepared using an excipient compound and PEG, where the PEG was intended to simulate a therapeutic PEGylated protein that would be used in a therapeutic formulation, and where the excipient compounds were provided in the amounts as listed in Table 13. These formulations were prepared by mixing equal volumes of a solution of PEG with a solution of the excipient. Both solutions were prepared in DI-Water.

The PEG solution was prepared by mixing 16.5 g of poly(ethylene oxide) average Mw 100,000 (Aldrich Catalog #181986) with 83.5 g of DI water. The mixture was stirred overnight for complete dissolution.

The excipient solutions were prepared by this general method and as detailed in Table 13 below: An approximately 20 mg/mL solution of potassium phosphate tribasic (Aldrich Catalog #P5629) in DI-water was prepared by dissolving 0.05 g of potassium phosphate in 5 mL of DI-water. The PEG excipient solution was prepared by mixing 0.5 mL of the PEG solution with 0.5 mL of the excipient solution and mixed by using a vortex for a few seconds. A control sample was prepared by mixing 0.5 mL of the PEG solution with 0.5 mL of DI-water. Viscosity was measured and results are recorded in Table 13 below.

TABLE 13 Excipient Viscosity Test Concentration Viscosity Reduction Number Excipient (mg/mL) (cP) (%) 22.1 None  0 79.7 0 22.2 Citric acid Na salt 10 74.9 6.0 22.3 Potassium 10 72.3 9.3 phosphate 22.4 Citric acid Na 10/10 69.1 13.3 salt/Potassium phosphate 22.5 Sodium sulfate 10 75.1 5.8 22.6 Citric acid Na 10/10 70.4 11.7 salt/Sodium sulfate

Example 23 Improved Processing of Protein Solutions with Excipients

Two BGG solutions were prepared by mixing 0.25 g of solid BGG (Aldrich catalogue number G5009) with 4 ml of a buffer solution. For Sample A: Buffer solution was 20 mM histidine buffer (pH=6.0). For sample B: Buffer solution was 20 mM histidine buffer containing 15 mg/ml of caffeine (pH=6). The dissolution of the solid BGG was carried out by placing the samples in an orbital shaker set at 100 rpm. The buffer sample containing caffeine excipient was observed to dissolve the protein faster. For the sample with the caffeine excipient (Sample B) complete dissolution of the BGG was achieved in 15 minutes. For the sample without the caffeine (Sample A) the dissolution needed 35 minutes.

Next the samples were placed in 2 separate Amicon Ultra 4 Centrifugal Filter Unit with a 30,000 molecular weight cut off and the samples were centrifuged at 2,500 rpm at 10 minutes intervals. The filtrate volume recovered after each 10 minute centrifuge run was recorded. The results in Table 14 show the faster recovery of the filtrate for Sample B. In addition Sample B kept concentrating with every additional run but Sample A reached a maximum concentration point and further centrifugation did not result in further sample concentration.

TABLE 14 Sample B Sample A filtrate collected filtrate collected Centrifuge time (min) (mL) (mL) 10 0.28 0.28 20 0.56 0.61 30 0.78 0.88 40 0.99 1.09 50 1.27 1.42 60 1.51 1.71 70 1.64 1.99 80 1.79 2.29 90 1.79 2.39 100 1.79 2.49

Example 24 Protein Formulations Containing Multiple Excipients

This example shows how the combination of caffeine and arginine as excipients has a beneficial effect on decreasing viscosity of a BGG solution. Four BGG solutions were prepared by mixing 0.18 g of solid BGG (Aldrich catalogue number G5009) with 0.5 mL of a 20 mM Histidine buffer at pH 6. Each buffer solution contained different excipient or combination of excipients as described in the table below. The viscosity of the solutions was measured as described in previous examples. The results show that the hindered amine excipient, caffeine, can be combined with known excipients such as arginine, and the combination has better viscosity reduction properties than the individual excipients by themselves.

TABLE 15 Viscosity Viscosity Sample Excipient added (cP) Reduction (%) A None 130.6 0 B Caffeine (10 mg/ml) 87.9 33 C Caffeine (10 mg/ml)/Arginine 66.1 49 (25 mg/ml) D Arginine (25 mg/ml) 76.7 41

Arginine was added to 280 mg/mL solutions of BGG in histidine buffer at pH 6. At levels above 50 mg/mL, adding more arginine did not decrease viscosity further, as shown in Table 16.

TABLE 16 Arginine Viscosity added Viscosity reduction (mg/mL) (cP) (%) 0 79.0 0% 53 40.9 48% 79 46.1 42% 105 47.8 40% 132 49.0 38% 158 48.0 39% 174 50.3 36% 211 51.4 35%

Caffeine was added to 280 mg/mL solutions of BGG in histidine buffer at pH 6. At levels above 10 mg/ml, adding more caffeine did not decrease viscosity further, as shown in Table 17.

TABLE 17 Caffeine Viscosity added Viscosity reduction (mg/mL) (cP) (%) 0 79 0% 10 60 31% 15 62 23% 22 50 45%

EQUIVALENTS

While specific embodiments of the subject invention have been disclosed herein, the above specification is illustrative and not restrictive. While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims. Many variations of the invention will become apparent to those of skilled art upon review of this specification. Unless otherwise indicated, all numbers expressing reaction conditions, quantities of ingredients, and so forth, as used in this specification and the claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth herein are approximations that can vary depending upon the desired properties sought to be obtained by the present invention. 

What is claimed is:
 1. A liquid pharmaceutical formulation comprising a therapeutic antibody and a viscosity-reducing amount of caffeine, wherein (i) the viscosity of the formulation is at least about 50% less than the viscosity of a control formulation and is less than about 50 cP, (ii) the formulation contains at least about 100 mg/mL of the antibody, and (iii) the viscosity reducing amount of caffeine is about 22 mg/ml or less; wherein the control formulation does not contain the caffeine but is otherwise identical on a dry weight basis to the liquid pharmaceutical formulation.
 2. The formulation of claim 1, wherein the viscosity reducing amount of caffeine is 22 mg/ml or less.
 3. The formulation of claim 2, wherein the viscosity of the formulation is at least about 70% less than the viscosity of the control formulation.
 4. The formulation of claim 2, wherein the viscosity of the formulation is at least about 90% less than the viscosity of the control formulation.
 5. The formulation of claim 2, wherein the viscosity is less than about 20 cP.
 6. The formulation of claim 2, wherein the viscosity is less than about 10 cP.
 7. The formulation of claim 2, wherein the formulation contains at least about 200 mg/mL of the antibody.
 8. The formulation of claim 2, wherein the formulation contains at least about 300 mg/mL of the antibody.
 9. The formulation of claim 2, further comprising an additional agent selected from the group consisting of preservatives, surfactants, sugars, polysaccharides, arginine, proline, hyaluronidase, stabilizers, and buffers.
 10. The formulation of claim 2 wherein the formulation is suitable for injection.
 11. A liquid pharmaceutical formulation comprising a therapeutic antibody and a viscosity-reducing amount of caffeine, wherein (i) the viscosity of the formulation is at least about 50% less than the viscosity of a control formulation and is less than about 50 cP, (ii) the formulation contains at least about 200 mg/mL of the antibody, and (iii) the viscosity reducing amount of caffeine is about 30 mg/ml or less; wherein the control formulation does not contain the caffeine but is otherwise identical on a dry weight basis to the liquid pharmaceutical formulation.
 12. The formulation of claim 11, wherein the formulation contains at least about 300 mg/mL of the antibody.
 13. The formulation of claim 11, wherein the viscosity of the formulation is at least about 70% less than the viscosity of the control formulation.
 14. The formulation of claim 11, wherein the viscosity of the formulation is at least about 90% less than the viscosity of the control formulation.
 15. The formulation of claim 11, wherein the viscosity is less than about 20 cP.
 16. The formulation of claim 11, wherein the viscosity is less than about 10 cP.
 17. The formulation of claim 11, further comprising an additional agent selected from the group consisting of preservatives, surfactants, sugars, polysaccharides, arginine, proline, hyaluronidase, stabilizers, and buffers.
 18. The formulation of claim 11 wherein the formulation is suitable for injection. 